The existence of the pilomotor reflex (goose bumps) in humans is evidence that: a. we have structures and physiological responses that no longer serve their original function b. evolution always results in traits that confer an adaptive value c. humans share a common ancestor with geese d. humans are unique among all other mammals

The answer is a)  we have structures and physiological responses that no longer serve their original function

Explanation:

Goosebumps are a physiological phenomenon inherited from our animal ancestors, which was useful for them, but is not very helpful for us. Goosebumps, called the pilomotor reflex, appear due to an involuntary nervous system response. This primitive response occurs when the hair follicles are stimulated by specific nerves in the skin, which triggers the contraction of tiny muscle cells, known as hair erectors, located at the base of the hair follicles.

The contraction of these muscle cells slightly elevates the hair follicle, which causes the hair to rise from the surface of the skin. The pilomotor reflex usually occurs in response to cold temperatures or strong emotional or psychological stimuli.

the answer that best describes the relative refractory period in the neuron is the resting membrane potential is restored, but concentrations of sodium and potassium are not restored to their original state.

the refractory period is the time during which another stimulus given to the neuron will not lead to a second potential. thus, because na+ channels are inactivated during this time, additional depolarizing stimuli do not lead to new action potentials.  

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